The present disclosure relates generally to a dispensing apparatus, and particularly to a one-piece ventable piston for use in a dispensing apparatus.
Syringes and like dispensers in which a plunger or push rod is pushed to dispense product from a cavity are widely used for many applications from medicine to industrial activities. Generally, such dispensers will have a barrel or other container providing the cavity, a dispensing opening at one end, an opposing open end for filling of the product therein, and a piston for driving the product through the dispensing opening. Because it is desirable to avoid spillage of product during the filling process, air tends to get trapped ahead of the piston as it is pushed into the cavity after the cavity has been appropriately filled with the product. The trapped air will contract /expand under storage, shipping and dispensing conditions. This can result in the piston being pushed out of the cartridge, causing the contents to leak. During dispensing this air can create lead lag or bubbles, which will adversely affect the proper mix ratio. In order to eliminate the air from the cavity, various procedures have been utilized including a vent in the piston which is subsequently closed. If the vent is not completely closed, seepage of product past the vent will occur when the syringe is put into use. If the air is not completely evacuated from the syringe, the trapped air may interfere with the operation of the dispenser by causing disruptions in a smooth flow of product,
While existing vent means for a syringe-type dispensing apparatus may be suitable for their intended purpose, the art relating to a syringe-type dispensing apparatus would be advanced with a venting arrangement that does not require fabrication and assembly of multiple parts.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.